I just discovered something interesting today. Someone called Brian Provinciano, a Canadian programmer, game designer, and fan of the Grand Theft Auto series, is working on an unofficial Grand Theft Auto III port for the NES, entitled Grand Theftendo. Written in a 6502 Assembly Language called NESHLA, Grand Theftendo will be a chopped down version of GTA3 as it will feature only the "Portland" district of the game. "Staunton Island" and "Shoreside Vale" will not be available due to time constraints. More information about this port can be found here.